Liquid pump



R. S. BASSETT LIQUID PUMP Filed Dec. 13, 1930,

, :NVENTOR Patented A'ug. 4, 19'31 ROBERT S. BASSETT, O1*|` BUFFALO, NEW YORK LIQUID PUMP `App1ication lc-d December 13, 1930. Serial No. 502,138.

My invention relates to improvements in liquid pumps which will draw in both liquids and gases through the intake but from which the discharge of liquids only is desired from the outlet.

My invention relates more particularly to grease pumps for handling automobile transmission and differential grease which is pumped from small containers which are frequently emptied with the result that air enters the intake of the pump, the grease having been removed from the container. y y The object of my invention is to provide a vmeans to separate gases such as air from liquids such as grease and to discharge liquids only through the main outlet opening and to discharge the gases through a secondary opening. The result of my invention is to provide a practical method for the rapid dispensing p grease directly from a pipe Without the necessity of filling measuring containers with the grease to assure that air was not measured together with the grease by the measuring unit which in my drawing is shown as a liquid operated grease meter of the usual type.

Among the novel features of my invention are the installation within the pump cylinder of the means necessary to prevent gases from passingy out of the main discharge outlet of the pump. rlhe advantage of this construction is that these pumps are usually inserted through a circular hole in the top of the grease container so that it would be diiiicult, if not impossible in many cases, to have the lower art of the grease pump other than a cylinder without radial projections.

Another novel feature is the secondary discharge opening or openings for .the gases leading into the upper part of the grease container so that if small quantities of grease pass out with the gases they are returned to the main supply of grease automatically, thus preventing this grease fromgetting on the exterior o the grease container.

In my drawing the figure is a central vertical longitudinal view of my improved liquid pump, showing a section through the pump c linder and showing the outside of the liquid operated metering device and connecting piping. Pump cylinder l is within grease container Qand passes through grease container cover 3 all in the usual manner. Driving pinion 4 and rack 5 are shown of conventional construction for moving the piston rod 6 up and down within pump cylinder 1. The exact method of accomplishing this move ment is not limited to the construction shown but may be any conventional construction whereby piston rod 6 is given a reciprocating motion.

7 is the upper portion'o'f the pump, enclosing rack 5. 8 is the main delivery opening of the pump on which is mounted liquid operated meter 9 which is of the usual type. 10 is the discharge pipe or tubing leading from liquid meter 9 and may be fitted with a conventio'nal shutoit valve 11 which prevents the hose from draining when the pumping operation is stopped.

Elements 1 to 1l inclusive are all ont conventional design and are not limited to the exact construction shown.

At the bottom of pump cylinder 1 is a conventional foot valve l2. 13 is a piston engaging the walls of pump cylinder l and fitted with valve disc 14 to allow the passage oi liquid past piston 13 in 'one direction in the usuai manner. Foot valve 12 and piston assembly 13 and 111 may be any of a number of conventional types and are not limited to the exact construction shown as the air separating parts of my invention have been successfully used with a number ci diierent types of pistons and foot valves. 15 is a check valve mounted in the upper part of pump cylinder 1 which may be any ci several designs. Its construction is such that a slight pressure will be required to open it to allow the flow of grease from the inlet of the pump toward the main outlet of the pump. lit will substantially stop the low oi grease past it in the reverse direction.

ln the construction shown piston rod 6 passes through the center oi the valve which has the movable valve member 16 closely engaging piston rod 6. Piston rod 6 does not engage the other parts ci the valve in the drawing which will allow piston rod 6 to have slight bends in it without Wedging against check valve 15. #1"1 is' the check valve spring which can be omitted in some instances. 18 is the upward stop for movable valve mem- -ber 16 and is held firmly within pump cylinvalve but if piston rod 6 is not true throughout its entire length with pump cylinder 1 the construction shown for movable valve disc 16 is advisable. 20 and 20 are gas discharge openings or orifices. A single opening can be used, or, as shown in the drawing, more than one opening.

The operation of the pump is as follows: When, pump piston 13 moves downward the rease in the lower part of pump cylinder 1 1s forced through the piston to a' position immediately above it. lhenl pump piston 13 moves upward a fresh supp-ly of grease is sucked in through foot valve 12 to lill the space directly below piston 13. The grease directly above piston 13 is forced through check valve 15 and out through the liquid operated meter 9. As opening 20 is small the amount of grease which may pass out through it is negligible and does not affect the operation o f the pump. On the downward stroke of piston 13 check valve 15 holds the grease in the upper part of the pump.

When the level of the grease in container 2 is so low that the air directly above the surface of the grease can pass in through foot valve 12 there is a condltion which until my invention has been very difficult to overcome.

The object of my invention is removal of air and gases which get into pump cylinder l1 and such air or gases areprevented from reaching-liquid meter 9 by being forced out of pump cylinder l through opening 20. Prior to my invention attempts had, been made to mechanicallystbp the movement of piston 13 when the level of the grease was inear the bottom of the container but such constructions have not been practical.

When ases, `whichwill be considered to be air as 1s usually the case, enter foot valve 12 the below check valve 15 will be free to pass out through o ening 20. This is because when a mixture oi) grease and air is between piston 13 and check valve 15 within pump cylinder 1 the grease settles to the lower part of this s ace while the air rises to the upper part of t e s ace and collects just under check valve 15. en piston 13 is moved upward the air passes out through opening 20 easily and the pressure between piston 13 and check valve 15 is not Asufficient to open check valve a are forced along with the grease lthroug .piston 13 to apoint directly above 15 when air is present below check valve 15 and when such air is being forced out through opening 20. -As piston 13 vrises the air is forced out of opening M2O until a point is reached at which the body of grease above piston 13 reaches opening 20.

. It is a Well `known fact that the flow of a liqudthrough an orifice especially viscous liquids is lower than the flow of a gas through the same orifice. Because of this physical law a large amount of air can escape through opening 20 but only a negligible amount of heavy viscous liqulds such as grease as is used for lubricating automobile transmissions and differentials. The `small amount of grease which passes out through opening 2O 1s automatically returned to the mam body of grease held within container 2. The use of the flow characteristics of a small orifice .when passing cases as compared to that when passing liquids especially viscous ones is novel in a liquid pump especially in conjunction with a check valve directly above such orifice as shown in my drawing.

A further refinement 'of my invention which improves it slightly but which adds considerably to the cost is the use of' sliding valve 21. This valve is mounted around piston rod 6 just below check valve 15 and closely engages the inner wall of pumpI cylinder 1. It is a loose iit around piston rod 6 so tht grease may pass between it and piston ro 6. l

22 is a stop to restrict the downward movement of sliding valve 21. When sliding valve 21 is in its upper position it covers opening 20 and substantially stops the flow through such opening. The action of slidin valve 21 is as follows:

hen grease'passes upward through the pump between piston rod 6 and sliding valve 21 there .is an upward force exerted on sliding valve 21 due to the iluid friction of the grease flowing past the valve. rlhis force when the grease is flowing causes sliding valve 21 to move upward covering opening v20. This prevents any grease from passing through opening 20 when only grease is present around sliding valve 21. On the other hand, when air is passing through the pump cylinder around sliding valve 21 it 'lows between sliding valve 21 and piston rod 6 easily,

piston type of pump, nevertheless my invention also covers the use of the flow retardingcheck valve and the gas discharge openings 1n connect1on w1th other types of liquid This refinement raideur circulating means other than a reciprocating piston, as the dow retarding valve and gas discharge openings will function equally well regardless oi the exact type of liquid circulating means as to their ability to prevent air and other gases from passing beyond the flow retarding check valve i Having thus described my invention what l claimas new and desire to secure by Letters of Patent is:

l. ln a liquid pump of the measuring type; a liquid operated meter; a pump inlet opening; a main delivery opening leading to the liquid operated meter; a liquid circulating device between said openings; a flow retarding check valve between said liquid circulating device and said main delivery opening; and a gas discharge opening between said check valve Aand said liquid circulating device, substantiaiiy as and for the purpose described.

2. ln a iiquid pump of the measuring type; a liquid operated meter; a pump inlet opening; a main delivery opening leading to the liquid operated meter; a liquid circulating device between said openings; a flow retarding valve -between said liquid circulating device and said main delivery opening; a liquid supply container surrounding said inlet opening; and a gas discharge opening from the dow of liquid between said valve'and said liquid circulating device, discharging into said liquid supply container, substantially as and for vthe purpose described.

3. In a iquid pump of the measuring type; a liquid o erated meter; a pump inlet opening; a main delivery opening leading to the liquid operated meter; `a pump piston within said pump between said openings.; a flow retarding check valve between said piston and said main delivery opening, and a secondary discharge opening between said check valve and said piston, substantially as and for the purpose described. l

d. ln a liquid pump of the measuring type; a pump inlet opening; a main delivery opening; a pump piston within said pump between said openings; a dow retarding valve between said piston and said main delivery opening; a liquid supply container surroundin said inlet opening; and a secondary disc arge opening from the How of liquid between said valve and said piston discharging into said liquid supply container, substantially as and for the purpose described.

5. lln a liquid pump of the measuring type; a liquid operated meter; a main delivery opening leading to the liquid operated meter; a pump piston within said pump; a shaft operatively connected to said pump piston; a check vvalve between said piston and said main delivery opening, comprising a seat, and a movable valve disc closely engaging said shaft and radially movable relative to said seat; and a secondary discharge opening from said pump between said check valve and said piston, substantially as and for the purpose described.

6. In a liquid pump of the measuring type; a pump inlet opening; a main delivery open'- ing; a pump cylinder; a reciprocating pump piston within said' cylinder between said openings; a flow retardingyalve within said cylinder between said piston and said main delivery opening; and a secondary discharge opening in the Wall of said pump cylinder between said valve and said piston, and located closely adjacent to said valve, substantially as and for the purpose described.

7. In a liquid pump; a pump inlet opening; a main discharge opening; a pump cylinder; a reciprocating pump piston within said pump cylinder; a piston rod operatively connected to said pump piston; a. dow retarding check valve within said cylinder between said piston and said main discharge opening; a liquid supply container surrounding said inlet opening; a. gas discharge opening in the wall of said pump cylinder between said valve and said piston, located closely adjacent to said valve, and discharging intosaid li uid supply container; and a ring-shape sli ing valve member havin a path oit travel along the inner wall of sai pump cylinder, covering at one end of said path of travel said gas discharge opening, and encirclin said piston rod, substantially as and for t e purpose described.

-ROB'D S. BASSETT. 

